Spark-proof accelerator assembly



Oct. 30, 1-956 K B. 1. ULINSKI 2,769,043

SPARK-PROOF ACCELERATOR ASSEMBLY Filed June 29. 1954 Tifil.

16 2s 22 IO i .2. l a 20 25 2a a I 44 2e 24 z I HHHJJH m 37 27 J l 56/52 42 5O 47 5940 35 49 so 5o 45 38 \l INVENTOR 46 32 I a/hi/J/ 49 47 [llBY 1 6 l W 17 33 ATTORNEY United States Patent SPARK-PROGF ACCELERATORASSEMBLY Bronislaus I. Ulinski, Chicago, Ill., assignor to The Yale &Towne Manufacturing Company, Stamford, Conn., a corporation ofConnecticut Application June 29, 195%, Serial No. 440,010

9 Claims. (Cl. 200-18) This invention relates to a foot-operatedaccelerator for electric industrial trucks. More particularly, myinvention relates to an extremely novel accelerator assembly havingpedal-actuated means for closing in proper sequence a number of motorcontrol circuits in a truck of this type. My novel construction can bevery readily adjusted for closing the motor circuits in anypredetermined order but, nevertheless, is exceedingly simple andutilizes a relatively small number of parts. These parts are soconstructed and arranged as to enable the accelerator to operate withoutsparks that are exposed to the atmosphere so that the accelerator can besafely utilized in an environment where there is danger of fire orexplosion.

As one feature of my novel accelerator assembly, I utilize as twoprincipal parts a pedal and a support frame that are formed from sheetmetal. The frame supports a series of switches for the control circuits,and is formed at one edge to provide a fulcrum for the pedal. The sheetmetal pedal is bent angularly to form a seat to coact with the fulcrum,and has at one side of the seat an arm through which the switches areactuated. The portion of the pedal at the opposed side of the seat formsa tread for the foot of the driver. The support frame carries a springthat holds the pedal seated on the fulcrum to pivot on the supportframe, this spring acting further to rotate the pedal to a normalposition.

As a further feature, I equip the pedal arm with springpressed plungersto move the switches. These plungers are retained relatively to thepedal arm through means that enable the accelerator to be very readilyadjusted for moving the switches in any predetermined order. Eachplunger yields upon actuating its particular switch so that the pedalarm does not apply excessive pressure to the switch, regardless of theparticular adjustment of the plungers.

As a still further feature, my novel construction uses pro-assembledsnap-action switches of a standard commercial type. These switches haveenclosed contacts with operating buttons for moving the contacts, andare available with a pair of contacts that are normally open, ornormally closed, or with other standard contact arrangements. Switcheshaving different arrangements of contacts are readily substituted on thesupport frame of my novel accelerator, and I can select those switchesthat are suited for a particular motor control circuit. This feature,together with the adjustable action of the plungers on the pedal arm,makes my novel accelerator very versatile and easily adapted to controldifferent types of circuits.

1 have thus outlined rather broadly the more important features of myinvention in order that the detailed description thereof that followsmay be better understood, and in order that my contribution to the artmay be better appreciated. There are, of course, additional features ofmy invention that will be described hereinafter and which will form thesubject of the claims appended hereto. Those skilled in the art willappreciate ice that the conception on which my disclosure is based mayreadily be utilized as a basis for the designing of other structures forcarrying out the several purposes of my invention. It is important,therefore, that the claims be regarded as including such equivalentconstructions as do not depart from the spirit and scope of myinvention, in order to prevent the appropriation of my invention bythose skilled in the art.

Referring now to the drawing:

Fig. l is a side view of my novel control assembly, partly in section.

Fig. 2 shows the accelerator with the pedal in depressed position.

Referring now more particularly to the drawings, the numeral 10indicates generally the sheet metal support frame of my novelaccelerator assembly. This support frame 10 has a vertical bracketportion 11, and a horizontal upper arm 12 that is attached to a flange13 on the bracket portion 11. I prefer to form an opening 14 through thearm 12 and flange 13 to receive a bolt, not shown, for mounting thesupport frame upon the truck. The left hand portion of the bracket arm12, as viewed in the drawing, is bent upwardly to form a flange 15having a transverse fulcrum edge 16. The lower end 17 of the verticalportion 11 of the support frame is bent into parallel relation with thehorizontal arm 12, thereby forming a stop for the pedal, as will bedescribed in due course.

To form the pedal, I bend a section of sheet metal angularly to form atread portion 18 and a downwardly extending arm 19, with the angularrelation of the portion 18 and arm 19 providing a seat 20 on the pedal.Preferably, also, the forward end of the tread portion 18 is bentdownwardly to form a stop 21 that is adapted to engage a part of thetruck when the pedal is depressed. The lower end of the pedal arm 19 isso positioned as to engage the stop 17 on the support frame 10 to limitmovement of the pedal in the opposed direction.

I utilize a coil spring 22 to hold the pedal seated on the fulcrum 16. Iparticularly mount the spring 22 on a rod 23 carried by the verticalportion 11 of the support frame and extending rearwardly past the pedalarm 19. The spring 22 is engaged between a seat 24 positioned againstthe rear face of the pedal arm 19 and a washer 25 that is retained onthe rear end of the rod 23 by nuts 26. It is important to observe herethat the coil spring 22 acts at a point that is a short distance belowthe fulcrum 16 to press the pedal arm 19 toward the stop 17 on thesupport frame. The spring 22 thereby acts to hold the pedal seated uponthe fulcrum 16 while simultaneously pressing the pedal to a normalposition in which the tread 18 of the pedal is raised, as shown inFig. 1. When the tread 18 is depressed, as in Fig. 2, the pedal arm 19moves away from the stop 17 in the axis of the fulcrum 16, with the coilspring 22 still acting to hold the pedal seated upon the fulcrum.

I show at 27, 28, 29, 30 a series of switches of the type havingoperating buttons 31. These switches 27 to 30 are attached in a verticalrow to the front surface of the vertical frame portion 11 by screws 32,with the operating buttons 31 positioned in relatively large openings 33in the frame portion 11. Upon the rear surface of the vertical frameportion 11, I mount a block 34 of insulating material through screws 35.l utilize a gasket 36 between the support frame and the block 34, andalso a gasket 37 between the frame and the switches, whereby the switchoperating buttons 31 are completely enclosed. I form a bore 38 throughthe block 34 in aligned relation to each switch operating button 31, andI mount pins 39 to slide in these bores 38 to depress buttons 31. Theblock 34 has inclined cam surfaces 38a at the outer ends of the bores38, for reasons that will appear. A retaining ring 40 on each pin 39prevents the pin from sliding rearwardly out of its bore 38.

The arm 19 of the pedal carries a series of plungers 42, d3, d4, 45 inaligned relation to the switch operating pins 39. These plungers aremounted to slide in openings in the pedal arm 19, and a coil spring 46is engaged between arm 19- and a head 47 on one end of each plunger topress the plunger toward the corresponding switch operating pin 39. Theopposed end of each plunger 42, 45, id, 45 has a series of transverseopenings 5%, and a cross pin 48 in one of these openings in each plungerengages a washer 49 at the rear surface of the pedal arm 19 to limit themovement of the plunger relatively to arm 19. Thereby the springs 46 andcross pins 43 coact to determine a particular position of each plunger4?. to 45 relatively to the pedal arm 19. This enables the arm 19 toactuate each switch operating pin 39 at a particular point in itsrotating movement on the fulcrum 16 whereby to move the switches 27-30-in a predetermined order. The cam surfaces 38a on the block 34 willguide the heads 47 on the plungers into contact with the pins 39, in theevent that the plungers are not perfectly aligned with the pins. Becausethe pedal arm 19 acts on the plungers 42 to 45 through the springs 46,the arm 19 cannot apply excessive pressure to the switches. The order inwhich the pedal arm 19 moves the switches can very readily be changedmerely by inserting the cross pin 48 of each plunger into a differentone of the openings 5%} of the plunger.

When the coil spring 22 holds the pedal arm 19 in its normal positionagainst the stop 17 on the support frame It}, the arm 19 acts on theplungers 42 to 45 through springs 46 to hold the switch operating pins39 depressed, these pins in turn holding the switch buttons 31depressed. If we consider now that the truck driver depresses the treadportion 13 of the pedal to move the arm 19 away from the switches, theplungers 42 to 45 will move away from the switch operating pins 39,thereby effecting movement of the switches. Assuming for purposes ofdescription that the switch 30 is to move first, the cross pin 48 onplunger 45 will have been so adjusted, as in Figs. 1 and 2, that thisplunger moves away from the corresponding switch operating pin 39 beforemovement of the other plungers away from their switch operating pins. Asthe pedal arm 19 continues to move away from the switches, the arm willmove the plungers 44, 43, and 42 away from their corresponding switchoperating pins, with the particular order in which these plungers actdetermined by the adjustment of their cross pins 48.

If we assume that the motor control circuits are such that they are tobe closed when the accelerator pedal is depressed, the switches 27 to 34that are utilized are of the type having contacts that close when theiroperating buttons 31 are released. Thus, when the pedal spring 22 holdsthe arm 19 against the stop 17, as in Fig 1, the pedal will act throughplungers and operating pins to hold the switch buttons 31 depressed andthe motor control circuits will be open. As the driver depresses thetread 18 of the accelerator, the pedal arm 19 moves the plungers 42 to45 away from the operating pins 39 to relieve pressure on the switchbuttons 31, thereby causing the switches 27 to 30 to close the motorcontrol circuits in predetermined order.

I believe that those skilled in the art will now understand that I havecontributed an exceedingly novel accelerator assembly having veryconsiderable advantages. Notwithstanding its extreme simplicity, mynovel assembly is very veresatile and enables me to utilize standardcommercial switches suitable for controlling different types of motorcircuits, while also enabling me to change very readily the order inwhich the circuits are closed. In addition... my novel constructionenables the accelerator to operate without causing hazardous sparks.

I believe, therefore, that my invention will now be fully appreciated.

I now claim:

1. In a combination of the class described, a series of switches, asupport frame for said switches adapted to be mounted on an industrialtruck, a block on said support frame at one side of said series ofswitches, an operating pin for each switch mounted to slide in theblock, an edge portion on said support frame forming a fulcrumpositioned in an axis at one end of the block, a sheet metal pedal bentangularly to form a seat to coact with said fulcrum, a spring holdingthe sheet metal pedal seated on the fulcrum whereby to pivot relativelyto the support frame with an integral part of the pedal moving towardand away from the switch operating pins, 2. stop on the frame for themovement of the said part of the pedal toward the pins, said springpressing said part against its stop, a series of plungers carried bysaid part of the pedal in aligned relation to the switch operating pins,springs through which the pedal acts when against its stop to press theplungers relatively to the switch operating pins to hold each switch ina particular position, and means acting when the pedal moves away fromthe stop to hold each plunger against the pressure of its spring wherebyto enable the switches to move to an opposed position in predeterminedorder.

2. In a combination of the class described, a series of switches havingoperating pins or the like, a support frame for said switches adapted tobe mounted on an industrial truck, a means mounting said switches inspaced relation on said support frame, a fulcrum on said frame for apedal, a sheet metal pedal bent angularly to form a seat to coact withsaid fulcrum, a spring holding the sheet metal pedal seated on thefulcrum whereby to pivot relatively to the support frame with an arm ofthe pedal moving toward and away from the operating pins of saidswitches, a series of plungers carried by said arm of the pedal inalignment with said switch operating pins, springs pressing the plungersrelatively to the arm against said switch operating pins, and meanswhereby the pedal moves said plungers away from said switch operatingpins in predetermined order when said pedal is rotated on its fulcrum.

3. In a combination of the class described, a series of switches havingoperating pins or the like, a support frame for said switches adapted tobe mounted on an industrial truck, a means mounting said switches inspaced relation on said support frame, a fulcrum on said frame for apedal, a sheet metal pedal bent angularly to form a seat to coact withsaid fulcrum, a spring holding the sheet metal pedal seated on thefulcrum whereby to pivot relatively to the support frame with an arm ofthe pedal moving toward and away from the operating pins of saidswitches, a series of plungers carried by said arm of the pedal, springspressing the plungers relatively tothe arm against said switch operatingpins, cam means guiding said plungers into alignment with said switchoperating pins, and means whereby the pedal moves said plungers awayfrom said switch operating pins in predetermined order when said pedalis rotated on its fulcrum.

4. In a combination of the class described, a support frame adapted tobe mounted on an industrial truck, switch means on said support frame,an edge surface on said support frame forming a fulcrum, a sheet metalstrap bent angularly intermediate its length to form a seat at theinternal side of the bend therein, said seat lying against said fulcrumwhereby to pivot on the fulcrum relatively to the support frame, aspring coacting with said strap for holding said strap in one positionagainst said fulcrum, that portion of the strap at one side of said bendand fulcrum forming a foot containing portion of a pedal, and anintegral part of said sheet metal strap coacting with said switch meanswhen pivoting on the fulcrum to actuate said switch means,

5. In a combination of the class described, a support frame adapted tobe mounted on an industrial truck, switch means on said support frame,an edge surface on said support frame forming a fulcrum, a member bentangularly intermediate its length to form a seat at the internal side ofthe bend therein, said seat lying against said fulcrum whereby to pivoton the fulcrum relatively to the support frame, a spring coac-ting withsaid member at one side of said bend and fulcrum for holding said memberagainst said fulcrum, said spring by its coaction rotating the member inone direction on the fulcrum, a portion of said member at one side ofthe bend forming a foot contacting portion of a pedal, and an integralpart of said member coacting with said switch means when pivoting on thefulcrum to actuate said switch means.

6. In a combination of the class described, a series of switches, anactuating part in each switch, a support frame for said switches, anoperating member mounted for pivoting on said support frame, a series ofplungers mounted on said operating member with each plunger movable withsaid member to apply the plunger to one of the actuating parts of eachof said switches, a spring engaged between each plunger and theopera-ting member to press the plunger in one direction relatively tosaid operating member and toward its switch, means limiting the movementof each plunger by its spring, each spring yielding upon movement of itsplunger against its switch actuating part, and each spring being ofsufficient strength to effect operation of its plunger and switch partprior to yielding.

7. In a combination of the class described, a series of switches, anactuating part in each switch, a support frame for said switches, anoperating member mounted for pivoting on said support frame, a stop onsaid frame for the pivotal movement of the operating member, a series ofplungers mounted on said operating member with each plunger movable withsaid member to apply the plunger to one of the actuating parts of eachof said switches as the member moves toward its stop, a spring engagedbetween each plunger and the operating member to press the plungertoward its switch, means limiting the movement of each plunger by itsspring, each spring yielding upon movement of its plunger against itsswitch actuating part, and each spring being of sufficient strength toeffect operation of its plunger and switch part prior to yielding.

8. In a combination of the class described, a series of switches, asupport frame for said switches, a block mounted on said support frameat one side of said series of switches, an actuating pin mounted toslide in the block for moving each switch, an operating member mountedfor pivoting on said support frame, a series of plungers mounted on saidoperating member with each plunger movable with said member to apply theplunger to one of the actuating pins of each of said switches, a springengaged between each plunger and the operating member to press theplunger in one direction relatively to said operating member and towardits switch actuating pin, means limiting the movement of each plunger byits spring, each spring yielding upon movement of its plunger againstits switch actuating pin, and each spring being of sufiicient strengthto effect operation of its plunger and switch prior to yielding.

9. In a combination of the class described, a series of switches, anactuating part in each switch, a support frame for said switches, anoperating member mounted for pivoting on said support frame, a stop forthe movement of the operating member, a plunger for each switch, meansmounting the plungers in spaced relation on said operating member witheach plunger movable with said member whereby to apply the plungers inpredetermined order to the actuating parts of said switches, a springengaged between each plunger and the operating member to press theplunger in one direction relatively to said operating member and towardits switch, means limiting the movement of each plunger by its spring,each spring yielding upon movement of its plunger against its switchactuating part as the operating member moves against its stop, and eachspring being of sutficient strength to effect ope-ration of its plungerand switch part prior to yielding.

References Cited in the file of this patent UNITED STATES PATENTS1,641,099 Schuster et al Aug. 30, 1927 2,379,305 Kaminky June 26, 19452,524,026 Best Oct. 3, 1950 2,547,765 Lund April 3, 1951 2,661,402 BalchDec. 1, 1953

